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Explainer: What's happening with the Oxford/AstraZeneca vaccine and older people in Ireland?

The jab has been the subject of ongoing controversies in recent weeks.

IRELAND FACES HAVING to reconfigure its Covid-19 vaccination strategy after a decision was made not to inoculate patients over 70 with the Oxford-AstraZeneca vaccine for now.

The jab was once considered a ‘game-changer’ in the country’s vaccination plan because of the comparative ease with which it could be rolled out across the population.

The EU’s medicines regulator granted authorisation for the use of the vaccine last week, but the move was preceded by a decision by German authorities not to use it for over 65s.

Similar decisions in other European countries followed, before Irish authorities moved to recommend only using mRNA vaccines – like those developed by Pfizer and Moderna -  in older groups where it is practicable to do so.

So how will the recommendation of Irish health authorities impact the country’s vaccine strategy? 

What happened to the ‘game changer’ vaccine?

The AstraZeneca vaccine has long been viewed as a significant player in the global Covid-19 response, largely due to its affordability and how easily it can be stored.

In contrast to those developed by Pfizer and Moderna, which require temperatures much colder than a standard freezer to be stored, AstraZeneca’s jab can be stored as normal.

There is no extra cost to store the vaccine in a specialised freezer, and people like pharmacists and GPs can administer it because vaccines don’t have to be defrosted and transported from unique facilities.

However, the vaccine has also become the source of controversy in recent weeks, particularly after it emerged that initial supplies from the company to the European Union would be lower than expected.

That development sparked a furious row between Europe and the pharmaceutical company, which intensified last week when reports emerged in Germany that the efficacy of the vaccine was incredibly low in older age groups.

The daily Handelsblatt cited unnamed sources in a report last Monday which stated that the German government estimated the efficacy of the jab among over-65s at just 8%, while the tabloid Bild also cited sources who put the efficacy rate at less than 10%.

Those reports suggested that the German government did not expect the European Medicines Agency (EMA) to approve the vaccine for use in older age groups – which would have been a major setback for the continent’s Covid-19 response.

Both Germany’s health ministry and AstraZeneca rubbished the reports and said the data had been misrepresented, but the former’s statement offered a hint of things to come, noting that it was known that fewer older people were involved in initial AstraZeneca studies than in those carried out by other manufacturers.

By Thursday, a day before a decision on EMA approval for AstraZeneca was to be announced, Germany’s vaccine commission said it would not recommend the use of the vaccine for those aged over 65.

Several other countries followed suit, even after the EMA approved the vaccine for everyone over the age of 18 last Friday.

covid19-vaccination-officially-begins-in-kathmandu-nepal-27-jan-2021 A vial of Oxford-AstraZeneca vaccine SIPA USA / PA Images SIPA USA / PA Images / PA Images

Italy has said that vaccines by other companies should be given priority for the elderly.

France, Austria and Sweden have also limited the vaccine to under-65s only, Poland has approved it for under-60s only and Belgium will restrict its use to adults under age 55 following a recommendation from the country’s health regulator.

Finland, like Ireland, has recommended that the vaccine only be given to people under the age of 70.

Norway and Denmark also announced today that they are reserving the vaccine for under-65s only.

And Swiss regulators, who have given the green light to Pfizer and Moderna’s vaccines, have refused to authorise the AstraZeneca vaccine at all. Yesterday, they said data was not yet sufficient for them to do so, calling for “new studies” to be done into the jab.

What is the science?

Unlike the Pfizer and Moderna vaccines, which use messenger RNA (mRNA) technology and need to be stored at much lower temperatures, the vaccine from Oxford/AstraZeneca is a viral vector vaccine.

MRNA vaccines use only the virus’s genetic code, as opposed to conventional vaccines produced using weakened forms of the virus, and is injected into the body where it enters cells and tells them to create antigens.

These antigens are recognised by the immune system and prepare it to fight Covid-19.

No actual virus is needed to create an mRNA vaccine. This means the rate at which it can be produced is dramatically accelerated.  

However, the Oxford/AstraZeneca vaccine does not work like this.

It uses a harmless, weakened version of a common virus which causes a cold in chimpanzees. The virus has been genetically modified so that it is impossible for it to grow in humans – people who get the vaccine will not become ill with a chimpanzee cold.

The Oxford/AstraZeneca vaccine can be stored, transported and handled “at normal refrigerated conditions” of between two and eight degrees Celsius for at least six months – a far cry from the -70 degrees Celsius needed for Pfizer/BioNTech’s offering.

A study by Oxford University released yesterday, which has yet to be peer-reviewed, found that those vaccinated with a dose of AstraZeneca were 67% less likely to test positive with a PCR test. 

In initial studies last November, Oxford/AstraZeneca said the vaccine showed an average 70% effectiveness, which jumped to 90% depending on the dosage.

And major study yesterday found that a single dose of the Astrazeneca vaccine may reduce transmission of Covid-19 by two thirds.

When authorising the vaccine last week, the EMA said that four clinical trials had been carried out on the vaccine involving about 24,000 people and that it was shown to be safe.

The medicines agency said the vaccine demonstrated a 60% efficacy in the clinical trials – but there was a catch.

The statement from the EMA did make note of the fact that most of the participants in these vaccine studies were between 18 and 55 years old, adding that there were not enough results to provide a figure for how well the vaccine will work in over 55s. 

Although this was also caveated with a statement that suggested the vaccine would be effective among that age group, it appears to have made countries iffy about approving it in older groups until more data is available.

What is Ireland doing?

Yesterday, Ireland followed suit when the National Immunisation Advisory Committee (NIAC) recommended that people aged 70 and over in Ireland should receive mRNA vaccines – from Pfizer/BioNTech or Moderna – “where practicable and timely”.

The HSE also said the vaccines were “preferential” for older people, based on current evidence of the efficacy of mRNA vaccines against Covid-19.

Health Minister Stephen Donnelly accepted a recommendation from the Chief Medical Officer Dr Tony Holohan, who said that mRNA vaccines should be administered “to all those over 70 years in order to provide the highest level of protection available”.

coronavirus-wed-oct-7-2020 PA PA

NIAC Chair Professor Karina Butler acknowledged that the decision was taken because “there are limited clinical data” in relation to the AstraZeneca vaccine in older adults.

However, she added that there is “nothing to indicate” that the vaccine will be less effective than in the younger population.

HSE Chief Clinical Officer Dr Colm Henry also told RTÉ Radio yesterday that the move was based on the evidence that health authorities have currently. 

“That may change in time,” he said.

“We see new evidence in the AstraZeneca vaccine showing good efficacy in the UK over those people vaccinated, but at this point in time the advice we’re getting from the EMA through NIAC is that it’s preferential to give those Pfizer and Moderna vaccines to the over 70s, and we’re beginning that in mid-February.”

However, Ireland was expected to receive much higher volumes of the Oxford/AstraZeneca vaccine than those from Pfizer and Moderna.

Around 35,000 doses of the jab are due to be delivered to Ireland next week.

Although some vulnerable groups, such as nursing home residents, have already been vaccinated with Pfizer and Moderna’s jabs, Oxford/AstraZeneca’s was set to be used to ramp up the vaccination of older 70s.

That means that, in the short-term at least, plans for using the Oxford/AstraZeneca vaccine will have to change.

Tánaiste Leo Varadkar told that giving older people mRNA vaccines, rather than AstraZeneca’s is “more complicated” but that it shouldn’t delay the roll-out.

“We have to pivot and adapt. And we can, and we will,” he added.

HSE CEO Paul Reid also tweeted this morning that Ireland’s overall vaccine rollout will have “many twists and turns” in the first quarter of the year.

“So far we’ve met all challenges in a safe, effective, secure and timely manner,” he added. “Our plan is to meet the latest changing requirements in the same way.”

He also said at a HSE briefing this afternoon that the health service was now working through operational changes to re-adjust the country’s vaccine plan, and would present details on this to the government’s vaccine taskforce shortly.

Taoiseach Micheál Martin also said today that the HSE needed to “work out” the implications of a changed recommendation, but moved to reassure the country that there would be no delay in starting to vaccinated over 70s.

Contains reporting by Órla Ryan, Rónán Duffy and from © AFP 2021.

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